Parallel -axle and inner-axle rotary piston engine of trochoidal construction with a follow-up drive traveling in sliding bars and forcing the piston movements

ABSTRACT

This invention relates to an improvement in a parallel-axle and inner-axle rotary piston engine having a housing with radial seals and enclosing working chambers, a piston corresponding in the outer contour thereof to a basic trochoidal shape, a followup drive traveling in sliding bars and forcibly effecting the piston movement, a sleeve on the engine drive shaft to which sleeve the piston and parts of the follow-up drive are nonrotatably connected, the improvement comprising a plurality of pistons and coordinated working chambers mounted in tandem in the axial direction of the engine, the axes of symmetry of said working chambers being positioned in housings pivoted by an angular amount with respect to each other, and said pistons being mounted on said sleeve pivoted with respect to each other in each case by double the corresponding angular amounts.

United States Patent 1 I14 Dec. 2, 1975 1541 PARALLEL -AXLE AND INNER-AXLE ROTARY PISTON ENGINE OF TROCIIOIDAL CONSTRUCTION WITH A FOLLOW-UP DRIVE TRAVELING IN SLIDING BARS AND FORCING TI-IE PISTON MOVEMENTS [75] Inventor: Franz Huf, Konstanz, Germany [73] Assignee: Dornier System GmbH,

Friedrichshafen, Germany 22 Filed: May 31, 1974' 21 App1.No.:475,025

[30] Foreign Application Priority Data Aug. 7, 1973 Germany 2339911 [56] References Cited UNITED STATES PATENTS 298,952 5/1884 Donkin 418/58 1,887,884 11/1932 Eyston 418/58 3,311,094 3/1967 Kehl 418/58 3,744,940 7/1973 Pierce et a1 418/60 FOREIGN PATENTS OR APPLICATIONS 845,451 6/1970 Canada 418/60 1,905,526 8/1970 Germany 418/61 B Primary Examiner-John J. Vrablik Attorney, Agent, or Firm-James E. Bryan [57] ABSTRACT This invention relates to an improvement in a parallelaxle and inner-axle rotary piston engine having a housing with radial seals and enclosing working chambers, a piston corresponding in the outer contour thereof to a basic trochoidal shape, a follow-up drive traveling in sliding bars and forcibly effecting the piston movement, a sleeve on the engine drive shaft to which sleeve the piston and parts of the follow-up drive are non-rotatably connected, the improvement comprising a plurality of pistons and coordinated working chambers mounted in tandem in the axial direction of the engine, the axes of symmetry of said working chambers being positioned in housings pivoted by an angular amount with respect to each other, and said pistons being mounted on said sleeve pivoted with respect to each other in each case by double the corresponding angular amounts.

7 Claims, 16 Drawing Figures US. atent Dec. 2, 1975 Sheet 1 0f 9 US. Patent Dec. 2, 1975 Sheet 2 of9 3,923,430

U. atent Dec. 2, 1975 Sheet 3 0f 9 US. Patsnt 136311975 Shet4of9 3,923,430

FIG. 3b

US. Patent Dec. 2, 1975 Sheet 5 of9 3,923,430

FIG. 55

FIG. 30

HIZ

US. Patent Dec. 2, 1975 Sheet 6 of9 3,923,430

FIG. 46'

FIG". 3e

Hsz

US, Patent Dec. 2, 1975 Sheet 7 of9 3,923,430

FIG. 4b

US. Patent Dec. 2, 1975 Sheet 8 of9 3,923,430

n w 9 k M 3 W a 3 5 t IO US, Patent Dec. 2, 1975 Sheet 9 of9 3,923,430

PARALLEL AXLE AND INNER-AXLE ROTARY PISTON ENGINE F TEGCIIOIDAIL CONSTRUCTION WITH-ll A FOLLOW-UP DRIVE TRAVELING IN SLIDING EARS AND FGIIGING TllilE PISTUN MOVEMENTS Copending application Ser. No. 405,875, filed Oct. 12, I973, relates to a parallel-axle and inner-axle rotary piston engine including a housing with radial seais, forming working chambers, a piston corresponding in the outer contour thereof to a basic trochoidal shape, as well as a follow-up drive which travels in sliding bars and forcibly effects the piston movement. In the construction disclosed in this patent application, a cylindrical rotary body is positioned on the drive shaft of the rotary piston engine in a manner such as to be secure against relative rotation and is mounted eccentrically offset with respect thereto by the extent of the trochoid eccentricity; a sleeve is rotatably positioned on the rotary body. The sleeve serves as a carrier for the parts of the follow-up drive connected therewith so as to be secure against relative rotation, and for the piston.

The present invention relates to a further development of the rotary piston engine disclosed in the copending application, supra. It has the purpose of controlling the complicated rotary movement of several pistons by means of a single follow-up drive, and thereby affording the possibility of an easy balancing of the entire engine, as well as avoiding pronounced deadcenter positions of the entire engine.

In accordance with the present invention, this object is obtained in a rotary piston engine according to the copending application, supra in that, in the axial direction of the engine, several pistons and their coordinated working chambers are mounted in tandem, and the axes of symmetry of the working chambers being positioned in tandem in the axial direction, are positioned in the housing pivoted by an angular amount. The coordinated pistons are mounted in each case on the sleeve pivoted with respect to each other by double the corresponding angular amounts. The angular pivoting of the working chambers with respect to each other may have any amounts desired and is not limited, for example, to an orthogonal arrangement. A pronounced dead-center position of the engine no longer exists here since, while a piston, when considered individually, indeed may be positioned in a dead-center position, the remaining pistons will constitute, by virtue of their position, at all times a lever arm to the crankshaft or eccentric shaft.

According to an advantageous further embodiment of the present invention, the engine may be constructed in a building-block manner. Provided for this purpose are similar housing parts forming the working char bers with coordinated side walls. These individual building-block-like parts are added or incorporated into the total structure pivoted about the aforementioned angular amounts. It is possible in this connection to insert the follow-up drive as a complete structural part between two housing parts constituting working chambers. The follow-up drive, however, also may be subdivided in such a manner that a separate structural part is present for each of the directions of movement of the follow-up drive. These individual structural parts then may be inserted separately between different housing parts constituting working chambers.

Embodiments according to the present invention will now be further described hereinafter with reference to the accompanying drawings, wherein FIGS Ia and lb illustrate a rotary piston engine, with two pistons, in a transverse and a longitudinal crosssection, respectively,

FIG. 2a illustrates the follow-up drive,

FIGS. 2b and 2c illustrate mutually coodinated positions of the two pistons of FIG. I,

FIG. 3a illustrates a different position of the followup drive,

FIG. 3b illustrates schematically the arrangement of three pistons on an eccentric shaft,

FIGS. 30 through 3e illustrate mutually coordinated positions of the three pistons of FIG. 3b,

FIGS. la to ile illustrate an angular pivoting or displacement of the mounting of three pistons as compared to FIG. 3, and

FIG. 5 illustrates a rotary piston engine with three pistons and having a different arrangement of the follow-up drive.

FIG. 1111 is a cross-sectional view taken along line Ila-Ia in FIG. 1b. Shown therein is a rotary piston engine with two pistons. Selected for this embodiment is a piston having the simplest trochoidal shape, i.e. that of an epitrochoid I I (cardioid). It should be noted, however, that the present invention may be utilized with other trochoidal shapes as well.

The rotary piston engine has a continuous drive shaft I. The center thereof is designated with reference symbol M Seated on this drive shaft I in a manner such as to be secure against relative rotation is a rotary body. and the center M of the rotary body is offset with respect to the drive center M by the extent of the trochoid eccentricity E. The rotary body or eccentric is designated with reference numeral 2. Rotatably mounted on the eccentric 2 is a sleeve 3. Distributed thereon and secured thereto are the two pistons and parts of the follow-up drive. In FIG. 1a, R defines the crank circle which is described by the eccentric center M about the center M, of the drive shaft.

FIG. Ib shows clearly the building-block-like construction of the entire engine. All of the building-blocklike parts are composed of a housing including the working chambers and the two coordinated side walls. For the sake of clarity, the structural parts for the first piston are selected from the first decade, whereas the structural parts for the second piston are selected from the second decade, but the mutually corresponding parts at all times have the same final reference number. Analogously, in the subsequent description, also the structural parts for a third piston will be provided with reference numerals from the third decade. For this reason, the construction of the building block system is intended to be described herein merely on the basis of the example of the first piston.

The first piston is shown on the left-hand side in FIG. llb and has reference number 13. By means of a key 4 it is non-rotatably connected with the sleeve 3. The piston I3 is enclosed in a housing II which, however, is not clearly visible in FIG. Ib since it is covered at the sectional areas by the radial sealing strips lid. The housing II and the piston 113 are closed off laterally by means of the two side walls 117a and ll7b. Shown in the side walls and illustrated in a greatly simplified fashion is an axial seal I6. As apparent from FIG. Ia, within the housing 11 are sealing strip bearings which receive the radial sealing strips 14.

The construction of the second piston and of the working chambers thereof is identical. This piston has reference numeral 23, the housing thereof is identified with reference numeral 21, and the two side parts are defined with numerals 27a and 27b. Mutually corresponding parts or elements of the building block system are the same, with the exception, however, that the side walls positioned at the outer ends of the engine are slightly differently constructed as compared to the remaining side walls. In the case of FIG. 1b, accordingly, the inwardly-positioned side walls 17b and 27a are identical and also the two outwardly-positioned side walls 17a and 27b, while modified, are likewise the same with respect to each other. The difference resides merely in that the outwardly-positioned side walls 17a and 27b carry the bearings 7 for the drive shaft whereas the inwardly-positioned side walls 17b and 27a have recesses 8 for the rotatable eccentric 2.

Between the two pistons 13 and 23 is the follow-up drive. The complete attaching part for the follow-up drive is identified with reference numeral 5 in FIG. lb. In the embodiment under discussion here, it comprises sliding bars for the orthogonal directions of movement in the x and y directions of the drive. Depending upon the coordination regarding their direction of movement, the various parts of the follow-up drive have been given the additions of x or y to the respective reference numerals thereof. Thus, the eccentric discs 51): and 51 y, their coordinated frames 52x and 52y, and the sliding bars 53x and 53y are provided for the two directions of movement. The details of the follow-up drive will be further described hereinbelow in connection with FIG. 2a. Indicated on both sides of the engine as being mounted at the extreme ends of the drive shaft 1 are the flywheels 6.

Drawn in full lines in FIG. 1a is the working chamber shown on the left-hand side in FIG. 1b. The working chamber is enclosed by the housing 11. The inner delimitation 12 of the housing represents the outer envelope curve to the trochoidal form or shape of the piston 13. The working chamber formed or constituted by the envelope curve 12 has the axes of symmetry x and y In the axis y are the radial sealing strips 14, and additionally on the axis y are simultaneous points G and II of the trochoid. The piston 13 is illustrated in a central position between the two dead-center positions thereof (not shown). Drawn-in in dash-dotted lines, in FIG. la, is the working chamber for the piston 23 positioned on the right-hand side in FIG. lb. The inner delimitation of the housing 21 coordinated thereto is identified with reference numeral 22 and is equally provided as an envelope curve with respect to the trochoid. The axes of symmetry of the working chamber are pivoted about 90 as compared to the axes of symmetry of the above-mentioned working chamber. As a result thereof, the axis x coincides with the axis y of the first-mentioned working chamber, and furthermore, the axis y coincides with the axis x1112 of the first-mentioned working chamber. In the axis y are the radial sealing strips 24, and also positioned on the axis are the coordinated simultaneous points G and 1-1 of the trochoid. As has been already set forth, the axial directions of the two working chainbers are pivoted by 90 with respect to each other. The positions of the coordinated pistons 13 and 23 are pivoted on the sleeve 3 relative to each other by twice the angular amount, i.e. by 180. Even though the piston 23 in the position thereof as shown in the drawing is in a dead-center position, the piston 13 is not in a deadcenter position and, as a consequence, an effective lever arm for driving the engine is present at all times.

FIG. 1a also shows the intake and exhaust ports for the working chambers. For those working chambers located in the plane of the drawing and with the axes of symmetry x and y the intake ports are designated by E and the exhaust ports by A Similarly, the intake and exhaust ports located in the working chambers further to the rear, and parallel to the plane of the drawing, and having the axes of symmetry x and y are designated by E and A The ports in this plane are shown in phantom.

FIG. 2a illustrates the follow-up drive with the two directions of movement thereof. The directions of movement or axial directions have been defined with A1,; and y Shown in cross-section is the eccentric 2 with its center M which is displaced or shifted away from the center M of the drive shaft by the extent of the trochoid eccentricity E. Mounted by means of a key 4 so as to be secure against relative rotation on the sleeve 3 enclosing the eccentric 2 is one eccentric disc for each of the directions of movement x and y The eccentric disc which is coordinated to the direction of movement X is defined with reference numeral 51x, and the eccentric disc coordinated to the direction of movement yis identified with reference numeral 51y. The centers Mx and My of these two eccentric discs are positioned in each case in a mutually opposite direction and are removed from M by the value E. In FIG. 2a, the center My coincides with the center M,. The eccentric discs 51x and 51y are rotatably mounted in the coordinated frames 52x and 52y. The frame 52x is displaceable in the direction of the arrow on the sliding bar 53x in the direction of movement x Analogously, the frame 52y is displaceable in the direction of the arrow on the sliding bar 53y in the direction of movement In FIGS. 2b and 2c, the same position has been assumed for the follower gearing as has been represented in FIG. 2a. The position is easily recognizable from the position of the points M, and M The axes of the working chamber in FIG. 2b correspond again to the designation in FIG. la. They are identified with x and y The radial sealing strips 14 with their simultaneous points G and H are visible in the y -axis. They correspond fully to the designations in FIG. 1a. The piston 13 here is in the left dead-center position thereof.

The same position of the follow-up drive has been assumed also in FIG. 20, but the second working chamber which is formed by the envelope curve 22 is therein pivoted with the directions of the axes m and y thereof by as compared to FIG. 2b. The radial sealing strips 24 with the simultaneous points G and H thereof are drawn in a corresponding position on the y axis. As compared to FIG. 2b, the piston 23 is pivoted on the sleeve 3 by double the angular value of the axial pivoting, i.e. by The rotation of the piston is further elucidated on the basis of the piston point which is closest to the trochoid center M This point is identified, for the piston 13, with reference symbol K In FIG. 2b it is positioned to the right from the center M The corresponding piston point K for the piston 23 in FIG. 2c is pivoted precisely by 180 and positioned to the left from the point M on the axis y Even through, in the embodiment under discussion here, an orthogonal rotation of the system of axes has been assumed, it is nevertheless important that any other desired angular rotation or displacement of the axes is equally possible as long as the respectively coordinated piston is positioned on the sleeve 3 so as to be rotated by double the angular amount.

FIG. 3a illustrates again schematically a follow-up drive of the type of FIG. 2a, but in a somewhat different position. In the construction, however, the follow-up drive correspond to each other. Therefore, the reference numerals of FIG. 2a are reused here. To the positioning of the follow-up drive of FIG. 3a, i.e. to the position of the eccentric 2 with its center M relative to the drive center M belongs the arrangement of the pistons 13, 23 and 33 that has been shown in a longitudinal cross-sectional view and in a greatly simplified manner in FIG. 3b.

The working chambers of the pistons 13, 23 and 33 positioned in tandem in the axial direction on the sleeve 3 are displaced in each case by 60 with respect to each other with their coordinate system of axes. For the piston 13, the system of coordinate axes again is designated with x and y For the piston 23, the system of axes has been defined with x1122 and y The amount of the angular displacement of 60 is shown in FIG. 3d. For the third piston, i.e. the piston 33, the system of axes is designated with x and y and, in FIG. 3e, the angular displacement of the system of axes by 120 is shown, as compared to the system of axes of FIG. 3c. The radial sealing strips 14, 24 and 34 are indicated in each case in the y-axes of FIGS. 3c and 3d, and equally the coordinated simultaneous point pairs G H and G H and G H It is further apparent from FIGS. 30 to 3e that the position of the indicated piston points K K and K of the various pistons is in each case shifted or pivoted on the sleeve 3 by double the amount of the angular displacement of the system of axes, namely by 120 for FIG. 3d, and by 240 for FIG. 3e. The sequence of the angular displacement of the working chambers and of the coordinated pistons actually may be desired. Hence, it is not necessary to select the sequence of 60, 120 shown in FIGS. 30 to 3e; rather it is quite possible to select starting from the working chamber of FIG. 3c the sequence 0, 120, 60. The various angular values also may be selected to be varying amounts so that, for example, also a succession of the working chambers of 0, 75, 135, would be feasible.

FIG. 4a illustrates the same follow-up drive as FIG. 3a, but further rotated by an angular amount of 45 of the crankshaft. The further rotation of the crankshaft counterclockwise is indicated in FIG. 4a by It is apparent from the position of the various centers M M Mx, and My that the points Mx and My are positioned oppositely with reference to the center M It is further evident that the drive center M coincides with points Mx or My only in a very special position of the follow-up drive such as is the case, for example, in FIGS. 2a and 3a.

Shown in FIG. 4b is the corresponding of the piston 13, 23 and 33 for the position of the follow-up drive. Otherwise the arrangement of this figure corresponds to FIG. 3b. Also, FIGS. 4c and 4d correspond in the representations thereof to FIGS. 30 to 3e. The positions of the axis of symmetry of the: working chamber and of the envelope curve correspond completely to those of FIGS. 30 to 32. The sole difference as compared to FIGS. 3c to 3e is that the pistons 13, 23, and 33 are in each case further rotated, corresponding to the further rotation of the crankshaft, by 45, in a direction of rotation opposite to the direction of rotation of the crankshaft. The position of the indicated piston points K K and K is now as follows for K 0 45 45; for K 45 and for K 240 45 285".

On the basis of FIG. 3, structural possibilities are indicated in FIG. 5 relative to the construction of a rotary piston engine with three pistons. The reference numerals therefor are selected analogously to FIG. lb. Each piston and working chamber is enclosed by a housing. The housings are designated with reference numerals ll, 21 and 31. The side walls for the working chambers again are designated with 17a, 17b, and 27a, 27b, and 37a, 37b. The two outwardly-positioned side walls, here the side walls 17a and 37b, are identical with respect to each other, but slightly different than the other side walls which are identical to each other. The side walls 17a and 37b carry the bearings 7 for drive shaft 1. The other side walls have the recesses 8 to accommodate the rotary movement of the eccentric 2. In this manner it is readily possible with the building blocks to arrange several pistons, with coordinated working chambers, according to the building block principle on a single drive shaft 1 with the eccentric 2 and to have the piston rotation controlled by a single follow-up drive. Not only are all side parts identical, but also the housing parts 11, 21 and 31 are identical with respect to each other are are assembled merely pivoted by the specific angular values. Furthermore, the follow-up drive may be readily inserted therebetween, as shown in FIG. 1b. It is readily apparent from FIG. 1b that it is possible at any time to provide, for example, a further piston to the left of piston 13 and to the right of piston 23 in each case, and to pivot or displace the coordinate system of axes of the working chambers in each case by specific angular amounts. Thus, there would be two pistons provided in each case, for example to the left and right of the follow-up drive.

As compared thereto, the follow-up drive in FIG. 5 is subdivided into two separate structural parts from which one structural part is present for each direction of movement. Provided for the direction of movement x is the structural part identified with 5x, and for the direction of movement y the structural part identified with 5y. The structural part 5x is positioned between the housings 11 and 21 and the coordinated side parts 17b and 27a. The structural part 5y of the follow-up drive, on the other hand, is positioned between the housing 21 and 31 and is inserted between the side walls 27b and 37a. Despite the subdivision of the follow-up drive, the engine is as effective as the embodient represented in FIG. 1b.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. In a rotary piston engine of trochoidal construction having an inlet, an outlet, a drive shaft, and a piston designed as an epitrochoid 1:1, an inner housing wall conforming to the outer envelope curve of the epitrochoid, with radial seals and enclosing working chambers, and a follow-up drive effecting the planetary piston movement,

the improvement which comprises a single cylindrical body means nonrotatably mounted on the engine drive shaft and eccentrically offset with respect thereto by the extent of the trochoid eccentricity, said cylindrical body having a radius at least equal to the trochoid eccentricity plus the radius of the engine drive shaft,

sleeve means rotatably mounted on said cylindrical body means and serving as a carrier for elements of the follow-up drive non-rotatably connected thereto, and for the piston,

a plurality of pistons and coordinated working chambers mounted in tandem in the axial direction of the engine,

the axes of said working chambers being positioned in housings pivoted around the engine axis by an angular amount with respect to each other,

said pistons non-rotatably mounted on said sleeve being displaced, as compared to the central axis thereof, with respect to each other in each case by double the correspondingangular amounts,

and said follow-up drive being common to all said pistons.

2. A rotary piston engine according to claim 1 having a building-block-like construction from similar housing parts adapted to be inserted pivoted relative to each other by angular amounts, said housing parts having coordinated side walls, and said housing parts enclosing working chambers.

3. A rotary piston engine according to claim 1 in which the axes of symmetry of two working chambers mounted in tandem in the axial direction of the engine are pivoted by relative to each other.

4. A rotary piston engine according to claim 1 in which the axes of symmetry of three working chambers mounted in tandem in the axial direction of the engine are pivoted in each case by 60 relative to each other.

5. A rotary piston engine according to claim 1 including means whereby said follow-up drive is inserted as a complete structural unit between two housing parts forming working chambers.

6. A rotary piston engine according to claim 1 in which said follow-up drive is composed of separate structural elements respectively coordinated to one direction of movement on a sliding bar.

7. A rotary piston engine according to claim 6 in which the structural elements of the follow-up drive coordinated to the individual direction of movement are mounted between different housing parts forming working chambers.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,923,430 a DATED December 2, 1975 I Franz Huf It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line.46, after "are", the word the should appear. Line 63, "the" should read this Column 4, line 44, "follower gearing" should read follow-up e drive Column 5, line 13 "drive" should read drives Line 44, after "be", the word as should appear. Line 63, after "corresponding", the word position A should appear.

" Column 7, line 19, after "axes" the words of symmetry should appear.

Signed and Scaled this second Day of March 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oflatents and Trademarks 

1. In a rotary piston engine of trochoidal construction having an inlet, an outlet, a drive shaft, and a piston designed as an epitrochoid 1:1, an inner housing wall conforming to the outer envelope curve of the epitrochoid, with radial seals and enclosing working chambers, and a follow-up drive effecting the planetary piston movement, the improvement which comprises a single cylindrical body means nonrotatably mounted on the engine drive shaft and eccentrically offset with respect thereto by the extent of the trochoid eccentricity, said cylindrical body having a radius at least equal to the trochoid eccentricity plus the radius of the engine drive shaft, sleeve means rotatably mounted on said cylindrical body means and serving as a carrier for elements of the follow-up drive non-rotatably connected thereto, and for the piston, a plurality of pistons and coordinated working chambers mounted in tandem in the axial direction of the engine, the axes of said working chambers being positioned in housings pivoted around the engine axis by an angular amount with respect to each other, said pistons non-rotatably mounted on said sleeve being displaced, as compared to the central axis thereof, with respect to each other in each case by double the corresponding angular amounts, and said follow-up drive being common to all said pistons.
 2. A rotary piston engine according to claim 1 having a building-block-like construction from similar housing parts adapted to be inserted pivoted relative to each other by angular amounts, said housing parts having coordinated side walls, and said housing parts enclosing working chambers.
 3. A rotary piston engine according to claim 1 in which the axes of symmetry of two working chambers mounted in tandem in the axial direction of the engine are pivoted by 90* relative to each other.
 4. A rotary piston engine according to claim 1 in which the axes of symmetry of three working chambers mounted in tandem in the axial direction of the engine are pivoted in each case by 60* relative to each other.
 5. A rotary piston engine according to claim 1 including means whereby said follow-up drive is inserted as a complete structural unit between two housing parts forming working chambers.
 6. A rotary piston engine according to claim 1 in which said follow-up drive is composed of separate structural elements respectively coordinated to one direction of movement on a sliding bar.
 7. A rotary piston engine according to claim 6 in which the structural elements of the follow-up drive coordinated to the individual direction of movement are mounted between different housing parts forming working chambers. 